The present invention relates to cable retractors, and more particularly to a device for extending and retracting a first end of a length of cable as the second end of the length of cable is held stationary.
One common type of cable retractor, known as a “slip ring” style cable retractor, includes a housing and a drum positioned within the housing. The drum is connected to a spring for urging the drum to rotate, and the cable is wound around the drum as the drum rotates. Slip rings are used to convey the electrical energy from the moving portion of the cable retractor, generally a portion of the drum, to a stationary portion of the cable retractor. Although relatively easy to use, these slip ring style cable retractors suffer from a number of disadvantages. First, they can be a safety hazard when used in environments where there is a possibility of a spark from the slip rings setting off an explosion, or the possibility of shorting by the slip rings coming into contact with moisture. In addition, they are not conducive to use with cables that require a large number of electrical conductors, such as HDMI or VGA cables because it can be highly complex to create the numerous connections with slip rings. They also cannot be used with cables that require continuity, such as fiber optics.
One style of cable retractor that attempts to overcome the above noted shortcomings includes a stationary central drum surrounded by a plurality of outer rollers that are capable of revolving around the inner drum, such that retracted cable can be wound about the inner drum and an outer “drum” formed by the surfaces of the plurality of outer rollers. Examples of this style of cable retractor are shown in U.S. Pat. No. 6,375,109 to Liao and U.S. Pat. No. 4,132,367 to Meson. Both of these patents show examples of cables being wound into a housing around an inner drum and a series of planetary style outer rollers that orbit about the inner drum. This style of retractor enables extension and retraction of cable without the use of slip rings, but generally suffers in that they allow only a small payout of cable for a relatively large housing. The Meson device allows only side-by-side winding of the cable on the drums, which limits the amount of cable that can be retracted and/or requires a very large unit. The Liao device allows for overlapping layers of the cable, but does not enable side-by-side wrapping of the cable. Charging either of these devices to allow both side-by-side and overlapping winding of the cable would cause the device to bind during the retraction and/or extension of the cable. Further problems are caused by the fact that both of these devices require a tight bend in the cable at the location where the cable exits the central drum. Many commonly used cables see denigration in signal quality when the cables are bent to an amount that exceeds the cables minimum specified bend radius.